1. Field of the Invention
The present invention relates to a danger alarm system having a plurality of alarm circuits which are connectible, via call lines, to a central station in which the state of the individual alarm circuits can be determined in the exchange via testing devices and can be displayed by way of an evaluation of the individual alarm signals can be executed by way of a programmed control.
2. Description of the Prior Art
In security alarm systems, it is essential that faulty system parts be recognized and indicated. In addition, the system should be available i.e. be operational, as permanently and completely as possible. In conventional systems, for each call circuit a separate central component group is usually required which contains both evaluation and display elements and simply feeds alarm and interference reports to a superordinate common display or registration. The amount of information to be processed increases because of the constantly increasing number of alarm circuits and types of alarm circuits connected to an alarm system, and also because of the further development toward more and more accurate alarm circuits which display on an analogue basis. Thereby, increasing numbers of component groups are required, which at the same time leads to an increase of failure risk because of the increasing plurality of component parts.
In newer systems, a central data processing system is often employed for the processing of the greater amount of information, and also for the reduction of the number of component parts. Connected therewith, however, is the specific risk that the central component groups should at some time become inoperative, which would result in the failure of the entire alarm system.